# Databases > MySQL difference between Union All and full outer join

## bvani

Hi

can any one tell me the difference between "union all" and "full outer join"

thanks in advance

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## Barbie

The output record set in union all contains same number of columns as in the input tables. But it concatenates all the records of both the input tables in the output. Both the input tables should have the same number of columns and same data types for those columns.

But the full outer join concatenates the columns in both the table. No need for the input tables to have same number of records.

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## bvani

Hi Barbie

That was a significant input thank you

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## chskumar

UNION ALL: there is restriction for set operators, i.e. the columns in query 1 must match the columns in query2 in data type,order and number.

*some e.g.:*
display those who are emp as well managers(INTERSECT)
display those who are not managers (MINUS)
display those depts which do not have emp(MINUS)
dispaly those depts which have emp(INTERSECT) try these......


OUTER-JOIN: used on those tables that keep common columns just like EQUI-JION. but, the o/p will display some extra information which is available in only one of the two tables......

E.G.: 
display emp details along with coressponding department details and also display that department details which there are no emp....

than q 
sateesh

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## ksrinat

I am taking NT Backup for SAP in SQL Backend.   But Backup time is less than one minute and shows the result of backup as OK.  Is it correct or wrong .

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## madhavi Krishnarajpet

Full Outer join:
_a full outer join combines the results of both left and right outer joins. The joined table will contain all records from both tables, and fill in nulls for missing matches on either side_ 

example is: 
select * from employee full outer join department on employee.departmentid = department.departmentid;

Union All:
The union all operator is used to combine the result-set of two or more select statements and allows duplicate values.

Example is: select * from employees_norway union all select * from employees_usa;

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